STUDIES ON ISOLATED RAT ADRENAL CELLS I. CONTINUOUS FLOW AND BATCH INCUBATIONS

A procedure for the continuous flow incubation of isolated adrenal cells is described. In this way the advantages of continuous flow incubations of adrenal tissue are combined with those of isolated adrenal cells. Suspensions of isolated adrenal cells were prepared by a modification of the collagenase method. A sigmoid dose-response curve was obtained when these cells were incubated with ACTH in batch incubations. Under these conditions (in the presence of 1 mU ACTH/ml) the corticosterone production rate remained constant during at least 240 min. This production rate was linearly related to the number of cells. Pre-incubation of the cells during 3 h resulted in an increased response to ACTH. In continuous flow incubations without ACTH the corticosterone production was negligible. With 100 μU ACTH/ml corticosterone production increased sharply after a short lag period. A maximum was reached after 60–75 min followed by a slow decrease. Cells pre-incubated in the continuous flow apparatus had a slightly diminished ACTH response without loss of affinity to ACTH. The continuous flow incubation of isolated adrenal cells offers new possibilities for the dynamic study of steroid biosynthesis in vitro. The method may also be valuable to study processes in a wide variety of other tissues.